There was an article in the 1917 Popular Mechanics book : "The Boy Mechanic" about building a homebrew lathe using pipe flanges and steel pipe for the bed. It looked like it would work for wood and maybe even rudimentary metal projects where no precision would be needed. Pretty interesting article and very likely the origin of the homebrew you found. I would like to see a real picture and if is the same I could scan the article.

That looks like a much more sophisticated machine than the one in the article. My guess is that the pipe flanges are bolted on in place of what ever legs or stand it originally bolted to. I would question if you could get much stability with the pipe adapter... Something different for sure! I hope you will report how you come out with it.